Why I sweat so much. Could it be hot flash.?

Maybe. Do you always sweat or did it just starts? Hot flash is a possibility but if you've always sweat, you might have a condition called hyperhidrosis.
Hot flashes. Hot flashes are common in the peri menopausal age range all the way through the menopausal age range (age 40 through 65!). Make sure you see your doctor for full evaluation, including for thyroid issues. There are many natural remedies such as evening primrose pill, black cohosh, soy products. There are also prescription medications such as Gabapentin or an "anti-depressant" that are helpful.